modes of shipment using multiple modes is often missing; and (4) complications can result from situations in which the country of origin can change when the goods are substantially transformed prior to end use.

For data on exports, the BTS report also identified five deficiencies in the Commodity Flow Survey (CFS): (1) it excludes a number of industries; (2) it has substantial nonresponse and sampling variance for exports; (3) it is only collected every 5 years; (4) for over 30 percent of its export records, the port of exit is missing; and (5) it does not provide useful information on imports.

For data on imports, the BTS study listed five deficiencies: (1) the value of imports must be estimated from commodity code and weight; (2) truck traffic from maritime imports must be estimated by the total minus imports transported by rail, which ignores petroleum products and inland and coastal shipments by water; (3) allocation to the state level uses Port Import/Export Reporting Service (PIERS) data, for which the state of destination is often missing; (4) the state may be the address of the importer and not that of the destination; and (5) truck traffic from imports arriving by air is ignored.

Finally, the BTS report pointed out two problems in estimating transportation at the substate level: there is datedness and a lack of focus on foreign business in the County Business Patterns data, and there are missing values of various kinds in calculating the Oak Ridge National Laboratory’s (ORNL) highway network and the intermodal network.

To address these deficiencies, the BTS report listed five data needs: (1) data on shipment weight for imports transported by truck, to eliminate the need to estimate this by subtraction; (2) information on state and county of destination for imports and information on county of destination for exports, to eliminate the need to use PIERS data and the county allocation model; (3) information on the port of entry rather than the administrative port; (4) data on all modes of transportation used in shipping to a destination, in addition to the mode used when the cargo arrives in or departs from a U.S. port of entry; and (5) data on in-transit and transshipments.

The BTS report mentioned three possibilities for (additional) data collection that we review in this section: (1) obtaining access to currently restricted data; (2) expanding the information requested on administrative records; and (3) initiating a new survey. In addition, there are a number of emerging technologies that may be useful for this purpose; we consider them in the last part of this section.



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